Where does “nguyên âm đơn” come from?

nguyên âm đơn (Vietnamese) comes from Vietnamese nguyên âm, from Chinese 元 — monetary unit, "especially" RMB; yuan.

nguyên âm đơn (Vietnamese): monophthong

Definitions

  1. monophthong

Ancestry of “nguyên âm đơn”, step by step

nguyên âm đơn traces back through two separate lines of ancestry.

via Vietnamese nguyên âm

StepLanguageWordMeaning
1Vietnamesenguyên âmvowel
2Chinese元monetary unit, "especially" RMB; yuan

via Vietnamese đơn

StepLanguageWordMeaning
1Vietnameseđơnapplication, petition, request; alone, only
2Proto-Mon-Khmerɗuənwide hat of straw
Every word from Chinese 元 →Every word from Vietnamese nguyên âm →